The Architect of the Capitol ordered accelerated testing after the discovery that water from five drinking fountains in the Cannon building had potentially hazardous levels of lead.

That turned up the problems in the Rayburn building. The results, delivered to the AOC on July 8, showed “two office restroom sinks were above the EPA standard of 15 parts per billion (20 ppb and 30.7 ppb).”

“The House Superintendent’s Office notified these two offices on Friday, July 8, placed signage and will take maintenance action on the sinks,” the AOC 's email alert said. Of the 186 water samples collected in the Rayburn building, 176 came back beneath the 15 ppb threshold. AOC is still waiting for results on eight tests.

Lawmakers have asked for weeks that the AOC share more information about the water situation. Many questions remain about the effects of long-term exposure to lead-spiked water, particularly with regard to expectant mothers and underage children.

The Environmental Protection Agency warns that there is no known level of lead exposure that is considered safe.

Michael Lynch, medical director of the Poison Center at the University of Pittsburgh School of Medicine, said lead poisoning is especially harmful to the very young.

“A small amount of lead, infrequently ingested from drinking water, is unlikely to cause severe toxicity in an adult,” Lynch estimated.

Once a faulty water source has been discovered, Lynch said taking corrective action is essential.

Cleaning aerators, filters and flushing corroded pipes — steps the AOC outlined in its maintenance protocol — are, in Lynch’s opinion, a good place to start.

“More significant exposures may require larger-scale evaluation of the plumbing for potential repair and/or replacement,” Lynch said in an email. “Regardless, ongoing monitoring would be necessary to ensure that there is no ongoing exposure.”